Tony Blair is planning a radical overhaul of Britain's controversial human rights legislation after claims that the present laws put the rights of criminals above those of victims.

In a move which brought immediate criticism from human rights' experts, the Prime Minister wants the government to have the power to override court rulings. The move comes only days after Blair criticised a senior judge for preventing the deportation of nine Afghan refugees who hijacked a plane to Britain. Downing Street said he was determined to find a way around such 'barmy' court rulings.

Blair unveiled his plans in a letter to the new Home Secretary, John Reid, in which he set out his 'most urgent policy tasks'. Legal experts and civil liberties groups accused Blair of playing politics with fundamental rights. The Observer has obtained a copy of the letter, which says it is essential to 'ensure the law-abiding majority can live without fear'.

It adds: 'We will need to look again at whether primary legislation is needed to address the issue of court rulings which overrule the government in a way that is inconsistent with other EU countries' interpretation of the European Convention on Human Rights.'

A Downing Street source said a range of existing laws could be reviewed and new legislation was also possible. One option under consideration was to amend the 1998 Human Rights Act, which wrote the European Convention into British law, to require a 'balance between the rights of the individual and the rights of the community to basic security.' He said that 'although British judges should already take that balance into consideration, it's clear that sometimes they don't'.

He said the act could be further amended if British courts blocked moves to deport terror suspects on the basis of 'memorandums of understanding' that they would not be tortured. A further possibility would be for Britain to consider withdrawing from specific clauses of the European rights convention if they led to court rulings which placed 'community safety' at risk.

Blair's letter, one of a series to be released this week setting out his policy priorities for the major government departments, also stressed the need for Reid to deal urgently with the scandal of foreign prisoners which forced Charles Clarke out of the Home Office. In addition, the Prime Minister endorsed calls by the government's probation service watchdog for a tightening up of rules for the release of violent offenders after a rapist, Anthony Rice, went on to murder 40-year-old Naomi Bryant. The report said probation staff had been so 'distracted' by Rice's human-rights claims that they lost sight of their duty to protect the public.

But Shami Chakrabarti, director of the rights group Liberty, denounced Blair's initiative. 'This government is addicted to quick-fix legislation to distract attention from maladministration,' she said. 'Tough talk and tough legislation don't ensure that the prison service is run properly, or the probation service is run properly.'

'The sinister twist in this case is that the government's own Human Rights Act is being used as the target for tough talk. In fact, it's a very tame piece of rights legislation that doesn't, for instance, allow the courts to trump Parliament. Still, it is an important framework to give the courts a say to prevent the worst excesses of authoritarian government.'

Anthony Lester, the human rights lawyer and Liberal Democrat peer, was particularly scathing about Blair's response to the Afghan ruling: 'The Human Rights Act was one of the first constitutional reforms of this government, but the Prime Minister persists in undermining public confidence in the rule of law and the protection of human rights by the senior judiciary,' he said.

Blair's tough policy prescription for Reid came amid growing pressure from the police for tightened sentencing guidelines for violent offenders.

The Observer has learnt that the Police Federation, which represents the interests of 130,000 officers in England and Wales, will use its annual conference this week to vote on a motion calling for the government to overhaul the current sentencing regime under which offenders can qualify for early release after serving only half their sentence. The motion is expected to get overwhelming support.

'We need to ask whether we should tell people exactly how long they will serve and they serve it, rather than telling a person they've got seven years and in three years they are out,' said Jan Berry, chair of the federation.

The conference will hear that police are concerned there are insufficient resources being devoted to the supervision of offenders in the community.

'We're not saying community sentences can't work, but we shouldn't underestimate the time and investment community sentences take if they are to work,' Berry said. 'The criminal justice system has enough trouble establishing an audit trail of foreign prisoners, let alone managing offenders in the community so that the public are kept safe.'

The Human Rights Act (1998) came into force in the UK in 2000 and is viewed as a flagship piece of Labour legislation. The act incorporates into UK law the1950 European Convention on Human Rights, which makes a number of inalienable civil and political rights enforceable by the courts in England and Wales.

What does the convention establish?

The convention is divided into a series of 'articles'. Articles 2-14 establish the rights protected by the convention, such as the right to life, freedom from torture, inhuman and degrading treatment, the right to liberty and to a fair trial. Over the years a number of protocols agreed by the Council of Europe have been added to the convention. Some of the protocols deal with procedural issues, but some guarantee rights in addition to those included in the Convention. The UK has signed up to just two of the additional protocols.

Who interprets the convention?

The European Court of Human Rights (ECHR) is the international court set up to interpret and apply the Convention. Based in Strasbourg, it is made up of judges nominated by each of the member countries of the Council of Europe. Over the years there have been many cases in which the ECHR has found the UK in breach of the Convention. The fact it took so long for a British citizen to bring a case before the court was a major factor in convincing the government to incorporate the convention into UK law after Labour came to power in 1997.

Why is the Human Rights Act in the news now?

In the last week there has been widespread public disquiet at the way the act is being interpreted. Last week a judge ruled that nine Afghan asylum seekers who hijacked an aircraft to fly to Britain should not be returned to their country because to do so would be to risk subjecting them to 'inhuman or degrading treatment or punishment' and therefore a breach of their human rights. The Prime Minister described the verdict as 'an abuse of common sense'. The decision - like the claim that convicted rapist Anthony Rice, who went on to kill Naomi Bryant after release, was freed because to hold him any longer risked breaching his human rights - caused public outrage. To pillory the act, however, misses the point. The UK signed up to the convention in 1953. Even if we didn't have the act, the hijackers and Rice could have sought redress in Strasbourg. It would simply have taken them longer for their cases to be heard.

What could Tony Blair do to ensure the act wasn't interpreted in similar ways in the future?

The government is supporting a test case by the Netherlands to appeal against a ruling that prevents it from sending a suspected Algerian terrorist, Mohammad Ramzy, back to his native country. The case is wending its way through the European courts. In the interim, the new Home Secretary, John Reid, has announced that he is appealing against the decision that the Afghans must be given leave to remain and work in Britain. If that doesn't work, experts say, the government might be left with only the legal equivalent of a nuclear option. The article of the European convention under which they were originally allowed to stay - the Article Three anti-torture clause - is one of only three which member states can abandon only if they leave the convention altogether.

David Cameron has talked about pulling out of or repealing the act. Could he do that?

In theory, yes, and he first mentioned the possibility when standing for the party leadership last year, so he clearly feels it's an option. But Labour has portrayed the idea as an example of old-style Tory Euroscepticism that would in effect require leaving the EU, even though the convention has nothing to do with the EU. Cameron's aides say that the idea would be a temporary withdrawal from the European Convention with a view to negotiating 'appropriate' changes in the way clauses such as Article Three apply to deporting terror suspects or foreign criminals.